Fire-box door



June 24, 1930. J. G. ROBINSON FIRE BOX DOOR Filed July 22. 1929 4 Sheets-Sheet l J. G. ROBINSON FIRE BOX DOOR June 24, 1930.

Filed July 22. 1929 4 gheets-Sheet 2 i2 emf/0n FIRE BOX DOOR Filed July 22, 1929 4 Sheets-Sheet June 24, 1930. J. a. ROBINSON FIRE BOX DOOR Filed July 22. 1929 4 Sheets-Sheet 4 Patented June 24, 1930 TEYS UNITE JAY G. ROBINSON, OF CHICAGO, ILLINOIS FIRE-BOX DOOR Application filed July 22,

This invention relates to improvements in safety devices for locomotive fire doors, and more particularly to automatic or semi-automatically operated doors which are provided with means for cracking the doors, that is,

opening the doors a short distance and leaving them partially opened when it is de* sirable to permit air to enter through the doors in the regulation of the fire.

The locomotive doors are often cracked or left partially open for considerable periods of time, and during such periods, if a blow-out or explosion should occur in the fines or fire box, the steam and hot gases would be projected through the open fire doors and into the cab with dangerous and destructive effects.

The object of the present invention is to provide a safety device for automatically closing the doors instantly upon occurrence of a blow-out, thus preventing the escape of steam and hot gases through the fire door into the cab, as aforesaid.

In carrying out my invention, I provide means responsive to a blow-out pressure generated in the fire box for actuating the mechanism which brings about the automatic closing of the doors, and as herein. illustrated, I have shown the pressure responsive device as applied both to a fire door of the positive power closing type and to a fire door of the gravity closing type, although it will be understood that the invention is not limited to the specific types of closureoperating 5 mechanisms herein disclosed.

The invention may best be understood by reference to the accompanying drawings, in which Figure 1 is a face view of a fire door of the fluid-operated opening and closing type, to which my invention has been. applied, with portions of the power cylinder shown in section.

Figure 2 is an enlarged detail section of the operating valves of the power cylinder shown in Figure 1.

Figure 3 is an enlarged detail face view of the valve operating mechanism.

Figure 4 is a side view of the valve operating mechanism shown in Figure 3 with 1929. Serial No. 380,117;

the adjacent parts of the fire box and pressure responsive piston shown in section.

Figure 5 is-a fragmentary plan view of the operating mechanism, drawn to a smaller scale than Figures 3 and 4, and showing a modified form.

Figure 6 is a face view of another type of fire door in which the door is opened by power but closed by gravity, and showing my invention applied thereto.

Figure 7 is a side view of the fire door shown in Figure 6.

Figure 8 is a sectional view of a modified form of plunger and sleeve.

Referring to details of the drawings, and particularly to the embodiment of my invention shown in Figures 1 to 5, inclusive, the fire door therein disclosed is of the Shoemaker type well known in the art and characterized by having upwardly and downwardly opening door sections connected together by a balancing lever system, and 0perated by fluid pressure so as to either open or close the doors. The fire door has a frame 10 and upper and lower doors 11 and 12 hinged on studs 11 and 12 respectively, at one side of the frame 10 and arranged so as to be parted on a horizontal central line.

The lever system for operating the doors is shown in Figure 1, in which it will be seen that the upper door 11 is connected by link 13 to a lever 14 fulcrumed at 15. The lower door is connected by link 16 to lever 17 fulcrumed at pin 18.

The two doors are connected for balanced operation by means of a connecting lever 20 extending in a generally vertical direction and pivotally connected at its upper end to a pin 21 on the outer end of lever 14 and pivotally connected at its lower end to a pin 22 intermediate the ends of lever 17. The arrangement is such that the two doors are moved simultaneously in' opposite directions and are in balanced relation one to the other in all positions thereof.

Said doors are operated bymeans of a suitable fluid control device 24 including a piston rod 24 pivotally connected to a pin 25 at the offset portion of the connecting lever intermediate the. ends thereof. The doors may also be operated manually by a hand lever 23 connected to the upper door 11 or a hand lever 23 forming an cxtension of the lower lever 17.

The fluid control device iiidicated generally at 24 is of the well known Shoemaker type and includes a large piston and small piston 31 both connected to the piston rod 24 and working in a cylinder 32. Under normal operation of this type of mechanism, constant pressure is maintained in the space between the upper and lower pistons 30 and 31 by means of a pressure reservoir (not shown) connected to a duct 34 communicating with said piston intermediate its ends, as shown in Figures 1 and 2. This duct is supplied through passage 34 having a check valve 35 therein and leading to the constant pressure reservoir.

To open the door, air pressure is supplied to the top of the larger piston 30 through a duct 36. By reason of the resultant greater area of downward pressure, the pistons are forced downwardly with the piston rod 24 whereby the doors are opened. To close the door, pressure on the top of the large piston is released, whereupon the constant pressure acting between the large and small pistons causes the latter to move upwardly and restore the doors to closed position.

In order to crack the doors, a valve 37 is provided in the duct 34 which shuts off the air inflow from the reservoir and bleeds the air through a port 38, as shown in Fig ure 2. The doors may then be moved to any desired position by either hand lever 23 or 23 in which position they will remain, by reason of the fact that the doors counterbalance each other, and also the fact that the pressure on opposite sides of the pistons is counterbalanced and ineffective for moving the doors in either direction. The cracking valve 37 is controlled by a lever 40 and may be manually operated by a rod 41 extending to the opposite'side of the door to a point adjacent the hand lever 23, as shown in Figures 1 and 2.

Referring now more particularly to the subject matter of my invention, I provide a pressure responsive device disposed in the wall of the fire box, preferably at a oint adjacent the fire door. One form of this device is shown in Figures 1 and 4 in which it will be seen that a sleeve 43 is passed through the inner and outer boiler plates 44 and 45, this sleeve being open at both ends. A plug or piston is passed through the sleeve so as to be subjected to a sudden pressure inside the fire box and forced outwardly upon the occurrence of a blow-out. In the form shown in Figures 1 and 4, the plug comprises a rod 46 extending to a piston or plug member 47 working in the sleeve 43. The rod 46 is connected with the cracking or bleeder valve 37 through suitable linkages, herein consisting of a bell crank lever 48 pivoted on pin 49 carried on bracket 50 at one side of the cylinder 32 and connected by a link 51 to the outer end of lever 40 which operates said cracking valve. With this construction, the outward movement of the plug or rod 46 caused by a blow-out has the effect of throwing the valve 37 into position to immediately restore the supply of r pressure from the constant reservoir through duct 34 into the cylinder between the large and small pistons, thereby causing the door to be closed immediately, owing to the greater pressure upon the upper large piston 30.

Means are preferably provided for holding the pressure responsive device against movement in either direction caused by vibration or excessive jars or the effectof normal draft tending to draw the piston inwardly toward the fire box. Any suitable form of mechanical or frictional retarding device may be used. As indicated in Figure 4, the engaging surfaces of the piston and sleeve may be roughened as by shallow circumferential serrations, but with sufficient clearance between the piston and sleeve to permit movement of the former under the pressure of a blow-out.

It will be noted further that in the construction shown in Figures 3 and 4, the piston rod 46 is connected directly to the bell crank lever 48 and is movable every time the cracking mechanism is operated. Under many conditions this movement 47 of the piston 47 is desirable in order to remove dirt which may accumulate within the sleeve and thus keep the parts in operative condition. At the same time, however, it will be understood that accidental movement of the piston should be avoided as this might cause accidental operation of the cracking valve.

In the modified form of device shown in Figure 5, the rod 46 is provided with an elongated slot 46 at its end in which the pin 49 at one end of the bell crank lever 48 is movable. With this construction, the cracking valve may be operated in the usual manner without causing movement of the piston, but on occurrence of the blow-out the piston and rod 46 will be moved outwardly and insure actuation of the cracking valve so as to close the door, as above described.

Referring now to the application of my invention to a door of the gravity closing type, such as shown in Figures 6 and 7, the form of door therein disclosed is of the Franklin type also well known in the art. The main parts of this door comprise a frame and doors 61 and 62 pivotally mounted on pins 63 and 64, respectively, so as to be swung sideways and outwardly when opened. This type of door is designed to be opened by fluid pressure only, being closed by gravity. The door actuating mechanism need not be herein described in detail excepting to point out that the cracking of the doors is effected by means of the hand lever 65, said lever having a pivoted outer portion 65 which is held in locked position in one or more notches 66 on segment 67, by depressing the pivoted end portion 65* of said lever inwardly, as is best shown in Figure 7. In normal operation, the door may be closed by pulling the lever 65 outwardly so as to disengage it from one of the notches in which it is retained, whereupon gravity will cause the doors to be closed. In the form shown, the door is retained in fully opened position by engagement of the handle 65*" in notch 66, as indicated in dotted lines in Figure 6, at the lower end of the segment 67, while the doors may be cracked or held partially open by engaging said handle in the intermediate notch 66.

Referring now more particularly to the means for releasing the doors so as to cause them to immediately close upon occurrence of a blow-out, I provide a pressure responsive device extending through the inner and outer boiler plates 44 and 45 in the same manner as described in connection with the pressure responsive device shown in Figures 1 to 4, excepting that in the present instance a modified form of such device is utilized wherein a piston head 76 is movable within the sleeve 77, and a rod 78 supported in bearing 78 is connected between the piston and a tripping bar 79 suitably disposed along the side of rack 67 so as to be in position to engage the pivoted end portion 65 of the operating lever 65 and throw it outwardly from engagement with one of the notches 66 or 66 when the doors are held thereby in open position. IVhen the handle 65 is thus disengaged, the doors are immediately closed by gravity in the usual manner.

In many locomotives the boiler end is inclined upwardly and forwardly. In such engines, the above described sleeve 43, which will of course be set at a right angle to the boiler plates, would slope downwardly toward the interior of the fire box with the result that vibration would have a tendency to cause the piston 47 to ride inwardly toward the interior of the fire box. Such inward movement would be limited by the connection of the piston with the valve actuating gear or, if desired, can be further limited by a suitable stop placed at any convenient point, such as at the inner end of the sleeve 43. In Figure 8 I have shown the sleeve 43 provided with an annular stop-flange 80 at its outer end to restrain excessive outward movement of the piston and to prevent its being completely ejected in case of a blow-out-. Of course the same purpose could be accomplished by attaching a chain of suitable length to the pistonor piston rod and to the boiler end or in a variety of other Ways. A stop lug may also be formed at the inner end of the sleeve, such stop being conveniently formed after the piston is inserted and at the time the sleeve is welded to the inner boiler sheet.

I claim as my invention:

1-. In a locomotive, a fire box, a fire door, means for opening and closing said door, and other means responsive to pressure in said fire box for automatically closing said door.

2. In a boiler fire box, a door, means controllable by an operator for moving said door to open and closed positions, and means operable by abnormally high pressure inside of the fire box for moving said door to closed position.

3. In a boiler fire box, a door, means controllable by an operator for moving said door to and maintaining said door in closed, partially open or fully open position, and means operable by abnormally high pressure inside of the fire box for moving said door from open position to closed position.

4. In a locomotive, a fire box, a fire door, means for opening and closing said door, said fire box having an aperture therethrough, means movable relative to said aperture and responsive to a predetermined pressure in said fire box for automatically closing said door upon occurrence of a blowout.

In a locomotive, a tire box, a fire door, means for opening and closing said door, means for rendering said door closing means temporarily ineffective whereby said doors are retained in open position, and means responsive to predetermined pressures in said fire box for restoring the effectiveness of said door closing means.

6. In a locomotive, a fire box, a fire door, means for opening and closing said door, means for rendering said door closing means temporarily ineffective whereby said doors are retained in open position, said fire box having an aperture therein, and means movable relative to said aperture and responsive to predetermined pressure in said fire box for restoring the effectiveness of said door closing means.

7. In a boiler fire box, a door opening, a door normally closing said opening, means controllable by an operator for opening said door by fluid pressure, means for moving said door to open position when released from said fluid pressure, and means operable by abnormally high pressure in the fire box to return said door to closed position from said open position.

8. In a boiler fire box, a door opening, a door normally closing said opening, means controllable by an operator for opening said door by fluid pressure, means for moving said door to open position When released from said fluid pressure, and means operable by abnormally high pressure in the fire box to return said door to closed position from said open position by fluid pressure.

Signed at Chicago, 111., this 18th day of J Uiy; 1929.

JAY G. ROBINSON. 

